CN1898460B - Secondary air supply equipment and its control method - Google Patents

Abstract

An ECU (300) executes a program including the steps of: in a case where the air amount GA is equal to or larger than a predetermined air amount GA (0), which is an amount of air introduced into the engine (100), and the coolant temperature TW at the time of engine start is equal to or higher than the predetermined coolant temperature TW (0) (yes in step S200), the electromagnetic ASV (232) is opened (S202) while the vacuum pressure ASV (1) and the vacuum pressure ASV (2) are controlled to be closed and the air pump (200) is controlled to be stopped; detecting a pressure (S204); closing the electromagnetic ASV (S206); when a pressure change is detected with the electromagnetic ASV open (yes in step S400), it is determined that at least one of the vacuum pressure ASV (1) and the vacuum pressure ASV (2) has failed (S402), that is, one of the vacuum pressure ASV (1) and the vacuum pressure ASV (2) remains in an open state and cannot be closed.

Description

Secondary air supply equipment and its control method

technical field

The present invention relates to secondary air supply equipment and a control method thereof. More specifically, the present invention relates to a secondary air supply device capable of detecting a failure in the secondary air supply device and a control method thereof. the

Background technique

Secondary air supply equipment is known, which uses secondary air delivered under pressure from an air pump to supply the exhaust manifold so that CO and HC in the exhaust gas are combusted and converted into _CO2 and _H2 due to chemical reactions O.

Japanese Patent Application Publication No. JP 2003-83048 discloses a secondary air supply device in which it is possible to determine whether an abnormality occurs in a component of the secondary air supply device. The secondary air supply apparatus disclosed in Japanese Patent Application No. JP 2003-83048 includes: a secondary air supply passage for supplying secondary air to a portion upstream of an exhaust control device in an exhaust system of an internal combustion engine; /closing section which opens/closes the secondary air supply passage; check valve which is provided downstream of the opening/closing section; pressure sensor which is provided in the secondary air supply passage; abnormality detection section which is based on the Detected pressure values and pressure change values to detect anomalies in components. When the opening/closing part is controlled to open and close the secondary air supply passage, the abnormality detection part drives the air pump, and detects the outlet pressure of the air pump, thereby detecting blockage of the secondary air supply passage. the

In the secondary air supply apparatus disclosed in Japanese Patent Application Publication No. JP 2003-83048, since the pressure value and the pressure change value are obtained using a pressure sensor, the pressure of each component can be determined in detail based on the combination of the pressure value and the pressure change value. failure mode. Also, since the air pump is driven and it is determined whether the outlet pressure of the air pump decreases when the opening/closing portion is controlled to close the secondary air supply passage, it is possible to determine whether an abnormality has occurred in the air pump, and at the same time determine whether the secondary air supply passage has been blocked. the

However, in the secondary air supply apparatus disclosed in Japanese Patent Application Laid-Open No. JP 2003-83048, it may not be possible to accurately determine whether an abnormality has occurred. Preconditions for providing the secondary air equipment are providing an opening/closing section that opens/closes the secondary air supply passage and a check valve provided downstream of the opening/closing section. However, no consideration is given to secondary air supply equipment having a configuration other than this. Therefore, in secondary air supply equipment having a configuration other than this, it may not be possible to accurately determine whether an abnormality has occurred. Also, in the secondary air supply device disclosed in the aforementioned publication, the air pump is driven and the outlet pressure of the air pump is detected, thereby simultaneously determining whether the secondary air supply device is blocked. However, in some cases it is not appropriate to drive an air pump. the

Contents of the invention

The present invention has been proposed in order to solve the foregoing problems. Accordingly, it is an object of the present invention to provide a secondary air supply device or a control method of such a secondary air supply device that can accurately detect malfunctions. the

A first aspect of the present invention relates to a secondary air supply apparatus for an internal combustion engine provided with a plurality of cylinders, the secondary air supply apparatus supplies secondary air to a portion upstream of an exhaust gas control device. The secondary air supply device includes: an air pump supplying air under pressure; a first air passage through which the air delivered from the air pump under pressure can flow; a first open/close valve of the first air passage; a second air passage connected to the first air passage at a portion downstream of the first open/close valve and connected to the an exhaust passage of a predetermined cylinder among the plurality of cylinders; a second opening/closing valve that opens/closes the second air passage; a third air passage connected at a portion downstream of the first opening/closing valve to the first air passage, and the exhaust passage connected to it leads to a cylinder different from the predetermined cylinder to which the exhaust passage connected to the second air passage leads; open/close the a third opening/closing valve of the third air passage; a pressure detector performing detection of pressure in the first air passage, the pressure detector being arranged between the air pump and the first opening/closing valve between; the fault determination device, the fault determination device is controlled to open the first opening/closing valve, the second opening/closing valve and the third opening/closing valve are controlled to close, and the air When the pump is stopped under control, it is determined whether a malfunction has occurred in the secondary air supply device based on a result of detection performed by the pressure detector. the

According to the first aspect of the present invention, the first air passage is opened/closed by the first opening/closing valve, the second air passage is opened/closed by the second opening/closing valve, and opened by the third opening/closing valve / Close the third air channel. The pressure in the first air passage is detected by a pressure detector provided between the air pump and the first opening/closing valve. The failure determining means determines based on a result of detection performed by the pressure detector when the first opening/closing valve is controlled to be opened, the second and third opening/closing valves are controlled to be closed, and the air pump is controlled to be stopped. Determine if a failure has occurred in the secondary air supply equipment. For example, when a pressure change is detected by the pressure detector, it may be determined that exhaust gas flows back into the first air passage via at least one of the second air passage and the third air passage. In this case, it is considered that a malfunction has occurred in at least one of the second opening/closing valve and the third opening/closing valve, and at least one of the second opening/closing valve and the third opening/closing valve remains in an open state and cannot be closed. Therefore, when a pressure change is detected, it may be determined that a malfunction has occurred in at least one of the second on/off valve and the third on/off valve, ie, a malfunction in the secondary air supply device may be detected. Thus, it is possible to accurately detect a malfunction in the second opening/closing valve and the third opening/closing valve of the secondary air supply device. Therefore, it is possible to provide a secondary air supply device capable of accurately detecting failures. the

According to a second aspect of the present invention, in the secondary air supply device according to the first aspect of the present invention, the failure determining means determines that the secondary air supply device whether a fault has occurred. the

According to the second aspect of the present invention, when the amount of air introduced into the internal combustion engine is greater than a predetermined amount, it can be determined whether a malfunction has occurred in the secondary air supply device. When the amount of introduced air is large, the exhaust volume is also sufficiently large. Therefore, when at least one of the second opening/closing valve and the third opening/closing valve remains in an open state and cannot be closed, a pressure change caused by exhaust gas flowing back into the first air passage becomes large. Therefore, when at least one of the second opening/closing valve and the third opening/closing valve remains in an open state and cannot be closed, the pressure detection equipment can accurately detect a pressure change. Thus, the accuracy of detecting a malfunction in the secondary air supply device can be improved. As a result, malfunctions in the secondary air supply equipment can be accurately detected. the

According to a third aspect of the present invention, in the secondary air supply device according to the first aspect or the second aspect of the present invention, the failure determining means may determine the secondary air supply device when a change in pressure is detected by the pressure detector. A fault has occurred in the secondary air supply. the

According to the third aspect of the present invention, when a pressure change is detected by the pressure detector, it may be determined that the exhaust gas flows back into the first air passage via at least one of the second air passage and the third air passage. In this case, it can be considered that a failure has occurred in at least one of the second opening/closing valve and the third opening/closing valve, that is, one of the second opening/closing valve and the third opening/closing valve remains in an open state and cannot be closed. Therefore, when a pressure change is detected, it may be determined that a malfunction has occurred in at least one of the second opening/closing valve and the third opening/closing valve. That is, malfunctions in the secondary air supply equipment can be detected. Thus, it is possible to accurately detect a malfunction in the second opening/closing valve and the third opening/closing valve of the secondary air supply device. the

According to a fourth aspect of the present invention, in the secondary air supply apparatus according to any one of the first to third aspects of the present invention, the failure determining means may determine that the second open/close valve and the Whether or not a failure has occurred in at least one of the third opening/closing valves. the

A fifth aspect of the present invention relates to a secondary air supply apparatus for an internal combustion engine installed in a vehicle, which supplies secondary air to a portion upstream of an exhaust gas control device. The secondary air supply apparatus includes: a pressure detector performing detection of the pressure of secondary air delivered under pressure from the air pump; information obtaining means obtaining information related to noise heard by an owner of the vehicle; pump operation means for operating the air pump when the magnitude of the noise is greater than a predetermined value; failure determining means for determining the two Check if a malfunction has occurred in the secondary air supply unit. the

According to the fifth aspect of the invention, the air pump is operated when the magnitude of the noise heard by the owner of the vehicle is greater than a predetermined value. Then, the air pump is operated under the condition that it is difficult for the vehicle owner to hear the noise of the air pump due to other noises. Therefore, it is possible to reduce the possibility that the vehicle owner will feel uncomfortable due to the operating noise of the air pump. The pressure of the air delivered under pressure from the air pump is detected by a pressure detector. The failure determination means determines whether a failure has occurred in the secondary air supply device based on a result of detection performed by the pressure detector while the air pump is operated under control. For example, in a case where the pressure increase is not detected by the pressure detector even when the air pressure is increased by the operation of the air pump, it is determined that a malfunction has occurred in the pressure detector. Thus, a malfunction in the secondary air supply device can be detected, while reducing the possibility that the vehicle owner will feel uncomfortable due to the noise of the air pump. Therefore, it is possible to accurately detect a malfunction in the secondary air supply device by accurately operating the air pump. As a result, it is possible to provide secondary air supply equipment capable of accurately detecting failures. the

According to a sixth aspect of the present invention, in the secondary air supply apparatus according to the fifth aspect of the present invention, the information related to the noise includes a vehicle speed, a rotational speed of the internal combustion engine, and a throttle set in the internal combustion engine. at least one of the opening degrees of the valves. the

According to the sixth aspect of the present invention, at least one of the following information may be detected as noise-related information: a vehicle speed, a rotational speed of the internal combustion engine, and an opening degree of a throttle valve provided in the internal combustion engine. the

According to a seventh aspect of the present invention, in the secondary air supply apparatus according to the fifth or sixth aspect of the present invention, the internal combustion engine is provided with a plurality of cylinders. The secondary air supply device includes: i) a first air passage through which the air delivered under pressure from the air pump flows; ii) opening/closing of the first air passage a first opening/closing valve; iii) a second air passage connected to the first air passage at a portion downstream of the first opening/closing valve, and connected to the plurality of air cylinders iv) a second opening/closing valve that opens/closes the second air passage; v) a third air passage that is connected at a portion downstream of the first opening/closing valve to the first air passage, and the exhaust passage connected to it leads to a different cylinder than the intended cylinder to which the exhaust passage connected to the second air passage leads; vi) open/ A third opening/closing valve of the third air passage is closed. The failure determining means determines based on a result of detection performed by the pressure detector when the first opening/closing valve, the second opening/closing valve, and the third opening/closing valve are controlled closed. It is determined whether a malfunction has occurred in the secondary air supply device. the

According to the seventh aspect of the present invention, the first air passage is opened/closed by the first opening/closing valve, the second air passage is opened/closed by the second opening/closing valve, and opened by the third opening/closing valve / Close the third air channel. The failure determination means determines whether a failure has occurred in the secondary air supply device based on the result of the detection performed when all the opening/closing valves are controlled closed. Then, the air delivered under pressure from the air pump is bound, causing the pressure to increase. Therefore, it can be determined whether a failure has occurred in the secondary air supply device based on whether the pressure detected by the pressure detector increases. the

According to an eighth aspect of the present invention, in the secondary air supply device according to the seventh aspect of the present invention, the failure determining means determines that the failure in the secondary air supply device A failure has occurred. the

According to the eighth aspect of the present invention, when the pressure detector does not detect a pressure increase under the condition that the pressure of the air delivered from the air pump should be increased under pressure, it can be determined that a malfunction has occurred in the pressure detector. Therefore, when the pressure detector does not detect an increase in pressure, it can be determined that a malfunction has occurred in the secondary air supply device. the

According to a ninth aspect of the present invention, in the secondary air supply apparatus according to any one of the fifth to eighth aspects of the present invention, the failure determining means determines whether at least one of the pressure detector and the air pump A failure has occurred. the

Description of drawings

Fig. 1 is a control block diagram showing a secondary air supply device according to a first embodiment of the present invention;

2 is a flowchart showing a control structure of a program executed by the ECU of the secondary air supply apparatus according to the first embodiment of the present invention;

3 is a timing chart showing the states of the air pump, electromagnetic ASV, vacuum pressure ASV(1) and vacuum pressure ASV(2) controlled by the ECU of the secondary air supply apparatus according to the first embodiment of the present invention;

4 is a flowchart showing a control structure of a program executed by an ECU of a secondary air supply apparatus according to a second embodiment of the present invention. the

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals, and their names and functions are the same. Therefore, its detailed description will not be repeated. the

first embodiment

Referring to FIG. 1 , a description will be given of a vehicle including an internal combustion engine control apparatus according to an embodiment of the present invention. The vehicle includes an engine 100 and an electronic control unit (hereinafter, referred to as “ECU”) 300 . The secondary air supply device according to the embodiment of the present invention is realized by a program executed by the ECU 300, for example. the

Engine 100 is a V-type engine. But engine 100 is not limited to a V-type engine. Air is drawn in through an air filter 102 and then introduced into the engine 100 via an intake pipe 104 and an intake manifold 106 . Air is introduced from the intake manifold 106 into the combustion chambers of each of the eight cylinders 108 along with fuel injected from injectors (not shown). The number of cylinders is not limited to eight. the

The air-fuel mixture introduced into each cylinder 108 is ignited by spark plugs and combusted. Then, the engine 100 generates driving force. The combusted air-fuel mixture (ie, exhaust gas) is directed to exhaust manifolds 110 and 112 coupled to cylinders 108 . After being purified by the catalysts 114 and 116, the exhaust gas is discharged to the outside of the vehicle. The amount of air introduced into engine 100 is controlled by throttle valve 120 . Opening of throttle valve 120 is controlled by actuator 122 . the

When the catalysts 114 and 116 are cold, the purification capabilities of the catalysts 114 and 116 cannot be fully utilized. Secondary air is thus supplied to exhaust manifolds 110 and 112 . Since secondary air is supplied, CO and HC in the exhaust gas are combusted and converted into CO ₂ and H ₂ O due to chemical reactions.

In this embodiment of the invention, the air in the engine compartment is used as secondary air. To supply secondary air, an air pump 200 is provided. The air pump 200 delivers the air in the engine compartment under pressure into the first air passage 210 . the

An electromagnetic air switching valve (hereinafter, referred to as “ASV”) 212 is provided downstream of the air pump 200 in the first air passage 210 . The electromagnetic ASV 212 is selectively changed between an open state and a closed state based on a control signal sent from the ECU 300 . Therefore, the electromagnetic ASV 212 can open/close the first air channel 210. The second air passage 220 and the third air passage 230 are connected to the first air passage 210 . the

One end of the second air passage 220 is connected to the first air passage 210 at a portion downstream of the electromagnetic ASV 212. The other end of the second air passage 220 is connected to the exhaust manifold 110 connected to one set of the engine 100 . That is, the other end of the second air passage 220 is connected to an exhaust passage leading to the cylinders 108 provided in one group of the engine 100 . the

Similarly, one end of the third air passage 230 is connected to the first air passage 210 at a portion downstream of the electromagnetic ASV 212. The other end of the third air passage 230 is connected to the exhaust manifold 112 which is connected to another set in the engine 100 . That is, the exhaust passage to which the other end of the third air passage 230 is connected leads to a cylinder 108 different from the cylinder 108 to which the exhaust passage connected to the second air passage 220 leads. the

Vacuum pressure ASV(1) 222 is provided in the second air passage 220 . The vacuum ASV ( 1 ) 222 is connected to a vacuum switching valve (hereinafter, referred to as “VSV”) 224 . Similarly, a vacuum pressure ASV(2) 232 is provided in the third air passage 230 . The vacuum pressure ASV ( 2 ) 232 is connected to a vacuum switching valve (hereinafter, referred to as “VSV”) 234 . the

VSVs 224 and 234 are connected to vacuum pressure tank 240. The vacuum pressure tank 240 is connected to the intake pipe 104 at a portion downstream of the throttle valve 120 via a check valve 242 . the

Check valve 242 allows air to flow from vacuum box 240 to intake duct 104 . Additionally, check valve 242 inhibits air flow from intake duct 104 to vacuum pressure tank 240 . Then, the pressure in the vacuum pressure tank 240 becomes a vacuum pressure. the

Based on a control signal sent from the ECU 300, the VSV 224 switches between a state in which vacuum pressure is introduced from the vacuum pressure tank 240 to the vacuum pressure ASV(1) 222 and a state in which atmospheric pressure is introduced to the vacuum pressure ASV(1) 222. In the case where the vacuum pressure is introduced from the vacuum pressure tank 240 to the vacuum pressure ASV(1) 222, the vacuum ASV(1) 222 is opened. With atmospheric pressure introduced to vacuum pressure ASV(1) 222, vacuum pressure ASV(1) 222 is turned off. Thus, the vacuum pressure ASV(1) 222 may open/close the second air passage 220 . the

Similarly, based on the control signal sent from the ECU 300, the VSV 234 is between a state where the vacuum pressure is introduced from the vacuum pressure tank 240 to the vacuum pressure ASV(2) 232 and a state where the atmospheric pressure is introduced to the vacuum pressure ASV(2) 232 switch. In the case where the vacuum pressure is introduced from the vacuum pressure box 240 to the vacuum pressure ASV(2) 232, the vacuum ASV(2) 232 is opened. With atmospheric pressure introduced to vacuum pressure ASV(2) 232, vacuum pressure ASV(2) 232 is closed. Thus, the vacuum pressure ASV(2) 232 may open/close the third air passage 230 . the

With the solenoid ASV 212, the vacuum pressure ASV (1) 222 and the vacuum pressure ASV (2) 232 turned on, the air delivered under pressure from the air pump 200 passes through the first air passage 210, the second air passage 220 and the second air passage 220. Three air passages 230 are supplied to exhaust manifolds 110 and 112 . Then, secondary air is supplied to the exhaust passage connected to each cylinder 108 . the

ECU 300 receives signals indicative of the results of detection performed by air flow meter 302 , throttle opening sensor 304 , pressure sensor 306 , vehicle speed sensor 308 , crankshaft position sensor 310 , and coolant temperature sensor 312 . the

The air flow meter 302 detects the amount of air introduced into the engine 100 . A throttle opening sensor 304 detects a throttle opening. The pressure sensor 306 is disposed between the air pump 200 and the electromagnetic ASV 212 , and detects the pressure in the first air passage 210 . The vehicle speed sensor 308 detects the rotational speed of vehicle wheels (not shown). The ECU 300 detects the vehicle speed based on the rotational speed of the wheels of the vehicle detected by the vehicle speed sensor 308. Crankshaft position sensor 310 detects the rotational speed of the crankshaft of engine 100 , that is, engine rotational speed NE. The coolant sensor 312 detects the temperature of the coolant of the engine 100 . the

The ECU 300 performs calculations based on signals sent from the sensors, and correspondences and programs stored in the memory 320. Therefore, the ECU 300 controls devices installed in the vehicle so that the vehicle enters a desired state. Also, in this embodiment, the ECU 300 detects malfunctions in the electromagnetic ASV 212, the vacuum pressure ASV(1) 222, and the vacuum pressure ASV(2) 232. the

Referring to FIG. 2 , description will be made regarding the control structure of a program executed by ECU 300 of the secondary air supply apparatus according to this embodiment of the present invention. the

In step S100, ECU 300 determines whether an AI (air injection) execution condition is satisfied. The term "AI (air injection)" means "delivering secondary air under pressure using the air pump 200 so that the secondary air is supplied to the exhaust manifolds 110 and 112 connected to each cylinder". The AI execution condition is a condition for executing AI. The AI execution conditions include conditions related to the coolant temperature of the engine 100 , the time period elapsed since the engine 100 was started, the amount of air introduced into the engine 100 , and the like. Known general conditions are used as AI execution conditions. Therefore, a detailed description thereof will be omitted. If the AI execution condition is satisfied ("Yes" in step S100), step S102 is executed. If the AI execution condition is not satisfied ("No" in step S100), step S200 is executed. the

In step S102, ECU 300 operates air pump 200. In step S104, ECU 300 opens solenoid valve ASV 212. In step S106, the ECU 300 introduces the vacuum pressure from the vacuum pressure tank 240 to the vacuum pressure ASV(1) 222 using the VSV 224, so that the vacuum pressure ASV(1) 222 is opened. In step S108, ECU 300 introduces vacuum pressure from vacuum pressure tank 240 to vacuum pressure ASV(2) 232 using VSV 234, so that vacuum pressure ASV(2) 232 is opened. the

In step S110, ECU 300 determines whether an AI end condition is satisfied. The AI end condition is a condition for ending the AI. The AI end condition includes conditions related to the time period elapsed from the start of the AI, the temperature of the catalyst 116, and the like. Known common conditions are used as AI end conditions. Therefore, a detailed description thereof will be omitted. If the AI end condition is satisfied ("YES" in step S110), step S112 is executed. If the AI end condition is not satisfied ("No" in step S110), step S110 is executed. the

In step S112, ECU 300 ends AI. When the AI ends, the operation of the air pump 200 is stopped. Solenoid ASV 212, vacuum pressure ASV(1) 222 and vacuum pressure ASV(2) 232 are turned off. the

In step S114, the ECU 300 detects the back pressure against the air pump 200, that is, the pressure in the first air passage 210 based on the signal sent from the pressure sensor 306. In step S116, ECU 300 turns on electromagnetic ASV 212. the

In step S118, the ECU 300 detects the back pressure against the air pump 200, that is, the pressure in the first air passage 210 based on the signal sent from the pressure sensor 306. In step S120, ECU 300 turns off electromagnetic ASV 212. the

In step S200, the ECU 300 determines whether the air amount GA as the air amount introduced into the engine 100 is equal to or greater than a predetermined air amount GA(0), and the coolant temperature (coolant temperature) TW at the start of the engine 100 Is it equal to or higher than the predetermined coolant temperature TW(0). the

When the electromagnetic ASV 212, the vacuum pressure ASV (1) 222 and the vacuum pressure ASV (2) 232 are in the open state, the pressure sensor 306 can detect the pressure change caused by the exhaust gas flowing back into the first air passage 210, and the air volume GA (0) is the air volume in this case or a larger volume than the air volume in this case. For example, the coolant temperature TW(0) is a temperature corresponding to the temperature of the ECU 300 at which the ECU 300 can be operated. the

If the air amount GA is equal to or greater than the predetermined air amount GA(0) and the coolant temperature TW is equal to or higher than the coolant temperature TW(0) at engine start (YES in step S200), step S202 is performed. Otherwise ("No" in step S200), this routine ends. This routine may be configured such that step S202 is executed when a condition different from the conditions related to the air amount GA and the coolant temperature TW is satisfied in addition to the conditions related to the air amount GA and the coolant temperature TW. the

In step S202, when the air pump 200 is controlled to stop and the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 are controlled to be turned off, the ECU 300 turns on the electromagnetic ASV 212. the

In step S204, the ECU 300 detects the back pressure against the air pump 200, that is, the pressure inside the first air passage 210 based on the signal sent from the pressure sensor 306. In step S206, the ECU 300 turns off the electromagnetic ASV 212. the

In step S300, when the air pump 200 is controlled to stop and the electromagnetic ASV 212, the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 are controlled to be closed, the ECU 300 determines whether there is a pressure pulsation, that is, a pressure change. If there is a pressure change ("YES" in step S300), step S302 is performed. Otherwise ("No" in step S300), execute step S400. the

In step S302, the ECU 300 determines that a failure has occurred in at least one of the electromagnetic ASV 212 and the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232, that is, the electromagnetic ASV 212 and the vacuum pressure ASV(1) 222 and the vacuum At least one of the pressure ASV(2) 232 remains open and cannot be closed. the

In step S400, when the air pump 200 is controlled to stop, the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 are controlled to be closed, and the solenoid valve ASV212 is opened, the ECU 300 determines whether there is a pressure pulsation, that is, the pressure Variety. If there is a pressure change ("YES" in step S400), step S402 is performed. Otherwise ("No" in step S400), the routine ends. In step S402, the ECU 300 determines that a failure has occurred in at least one of the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232, that is, at least one of the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232. One remains open and cannot be closed. the

Hereinafter, the operation of the ECU 300 of the secondary air supply apparatus according to the embodiment of the present invention will be described based on the structure and flow that have been described above. the

When a driver turns on an ignition switch (not shown) and starts a vehicle system, it is determined whether an AI execution condition is satisfied ( S100 ). If the AI execution condition is satisfied (YES in step S100 ), as shown in FIG. 3 , the air pump 200 is operated at time point T(1) (S102). the

After operating the air pump 200, the solenoid ASV 212 is turned on at time T(2) (S104). Next, the vacuum ASV(1) 222 is turned on for a period T(3) (S106). Next, the vacuum pressure ASV(2) 232 is turned on at time point T(4) (S108). the

Then, the secondary air delivered under pressure from the air pump 200 is supplied to the exhaust manifolds 110 and 112 connected to each cylinder 108 via the first air passage 210, the second air passage 220 and the third air passage 230 ( That is, execute AI). the

In this case, when the AI end condition is satisfied (YES in step S110), the air pump 200 is stopped, and the electromagnetic ASV 212, vacuum pressure ASV(1) 222, and vacuum pressure ASV(2) 232 are turned off. Then, the AI is ended at the time point T(5) (S112). the

After the AI ends (S112), the pressure sensor 306 detects the pressure in the first air passage 210 (S114). Next, open the electromagnetic ASV 212 (S116) at time point T (6), and detect the pressure in the first air channel 210 again (S118). Next, at time point T(7), the electromagnetic ASV 212 is turned off (S120). the

If all of the electromagnetic ASV 212, the vacuum pressure ASV (1) 222, and the vacuum pressure ASV (2) 232 are closed in a controlled manner (i.e., during the time period from time point T(5) to time point T(6) ) there is a pressure pulsation as shown by the dotted line in FIG. the

In this case, it can be considered that electromagnetic ASV 212 and at least one of vacuum pressure ASV(1) 222 and vacuum pressure ASV(2) 232 remain open and cannot be closed. Therefore, if there is a pressure change (YES in step S300), it is determined that a malfunction has occurred in the electromagnetic ASV 212 and at least one of the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 (S302). the

Also, even in the case where there is no pressure change during the period from the time point T(5) to the time point T(6) ("No" in step S300), if the air pump 200 is controlled to stop, the vacuum pressure ASV (1) 222 and vacuum pressure ASV (2) 232 are controlled closed, when the electromagnetic ASV 212 is opened, that is, during the time period from time point T (6) to time point T (7), there is a dotted line shown in Figure 3 If there is a pressure pulsation, it can be determined that the exhaust gas flows back into the first air passage 210 . the

In this case, it can be considered that at least one of the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 is kept in an open state and cannot be closed, and thus the exhaust gas flows back through the second air passage 220 and the third air passage 230 to the first air channel 210 . the

Therefore, if there is a pressure change (YES in step S400), it may be determined that a failure has occurred in at least one of the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 (S402). the

Meanwhile, even if the AI execution condition (S100) is not satisfied, if the air amount GA (the amount of air introduced into the engine 100) is equal to or greater than the predetermined amount GA(0), and the coolant temperature at the start of the engine 100 is equal to or higher than the predetermined temperature TW(0) (YES in step S200 ), it is determined whether a failure has occurred in at least one of the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 . the

To determine whether a failure has occurred in at least one of vacuum pressure ASV(1) 222 and vacuum pressure ASV(2) 232, the vacuum pressure ASV(1) 222 and vacuum When the pressure ASV (2) 232 is controlled closed), the electromagnetic ASV 212 (S202) is opened. the

In this state, the pressure sensor 306 detects the pressure in the first air passage 210 (S204), and turns off the electromagnetic ASV 212 (S206). If there is a pressure change during the time period from the opening of the solenoid ASV 212 to the closing of the solenoid ASV 212, it may be determined that the exhaust gas is backflowing into the first air passage 210. the

In this case, it can be considered that at least one of the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 remains in an open state and cannot be closed, and therefore it is considered that the exhaust air passes through the second air passage 220 and the third air passage 230 At least one of them flows back into the first air channel 210 . the

Therefore, if there is a pressure change (YES in step S400), it may be determined that a failure has occurred in at least one of the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 (S402). the

At this time, the air amount GA (the amount of air introduced into the engine 100) is equal to or greater than the predetermined amount GA(0). Therefore, the displacement becomes sufficiently large, and the magnitude of the pressure change detected by the pressure sensor 306 becomes large. Therefore, the pressure sensor 306 can accurately detect pressure changes. Thus, failures in the vacuum pressure ASV(1) 222 and the vacuum pressure ASV(2) 232 can be accurately detected. the

As described above, the ECU of the secondary air supply apparatus according to the embodiment of the present invention turns on the electromagnetic ASV when the air amount GA (the amount of air introduced into the engine 100) is equal to or greater than the predetermined amount GA(0). At this time, the air pump is controlled to stop, and the vacuum pressure ASV(1) and vacuum pressure ASV(2) are controlled to be closed. In this condition, if a pressure change is detected by the pressure sensor, the ECU 300 determines that a malfunction has occurred in at least one of the vacuum pressure ASV(1) and the vacuum pressure ASV(2), that is, the vacuum pressure ASV(1) and the vacuum pressure ASV(1) At least one of the pressure ASV(2) remains open and cannot be closed. Thus, in the secondary air supply apparatus in which the vacuum pressure ASV(1) and the vacuum pressure ASV(2) are provided instead of the check valve, a failure in the vacuum pressure ASV(1) and the vacuum pressure ASV(2) can be detected. the

Second embodiment

Referring to Fig. 4, a second embodiment of the present invention will be described. In the foregoing first embodiment, the ECU detects malfunctions in the electromagnetic ASV, the vacuum pressure ASV(1), and the vacuum pressure ASV(2). In the second embodiment, the ECU 300 detects a failure in the pressure sensor 306. The rest of the configuration in the second embodiment is the same as in the aforementioned first embodiment, and its function is the same as in the aforementioned first embodiment. Therefore, a detailed description thereof will not be repeated. the

Referring to FIG. 4 , a description will be given of a routine executed by ECU 300 of a secondary air supply apparatus according to a second embodiment of the present invention. In addition to the programs in the aforementioned first embodiment, ECU 300 executes the following programs. the

In step S500, ECU 300 determines whether AI is not executed. The sentence "AI is not executed" means that the aforementioned AI execution condition is not satisfied. If AI is not executed (YES in step S500), step S502 is executed. Otherwise ("No" in step S500), the routine ends. the

In step S502, the ECU 300 determines whether all of the following conditions are satisfied: the condition that the vehicle speed V is equal to or higher than the predetermined vehicle speed V(0), the condition that the engine speed NE is equal to or higher than the predetermined speed NE(0), and the throttle opening degree A condition that TH is equal to or greater than the predetermined opening degree TH(0). If the vehicle speed V is equal to or higher than the predetermined vehicle speed V(0), the engine speed NE is equal to or higher than the predetermined speed NE(0), and the throttle opening TH is equal to or larger than the predetermined opening TH(0) All are satisfied ("Yes" in step S502), then step S504 is executed. Otherwise ("No" in step S502), the routine ends. the

The routine may be configured to execute step S504 when at least one of the following conditions is satisfied: the condition that the vehicle speed V is equal to or higher than a predetermined vehicle speed V(0), the engine speed NE is equal to or higher than a predetermined speed NE( 0), and the condition that the throttle opening TH is equal to or greater than the predetermined opening TH(0). the

In step S504, ECU 300 operates air pump 200. In step S506 , ECU 300 detects the back pressure against air pump 200 , that is, the pressure inside first air passage 210 based on the signal sent from pressure sensor 306 . the

In step S508, the ECU 300 determines whether the pressure detected by the pressure sensor 306 has increased. If the pressure has increased ("YES" in step S508), step S510 is performed. Otherwise ("No" in step S508), execute step S512. the

In step S510, ECU 300 determines that pressure sensor 306 is normal. In step S512, the ECU 300 determines that a failure has occurred in the pressure sensor 306. At this time, "failure in the pressure sensor 306" means "failure in at least one of the pressure sensor 306 and the air pump 200". the

Hereinafter, the operation of ECU 300 according to this embodiment of the invention will be explained based on the structure and flow that have been described. the

When the vehicle system is being activated, in a case where the AI execution condition is not satisfied and the AI is not executed (YES in step S500), it is determined whether all of the following conditions are satisfied: the vehicle speed V is equal to or higher than the predetermined vehicle speed V(0) , the condition that the engine speed NE is equal to or higher than the predetermined speed NE(0), and the condition that the throttle valve opening TH is equal to or larger than the predetermined opening TH(0). the

If the vehicle speed V is equal to or higher than the predetermined vehicle speed V(0), the engine speed NE is equal to or higher than the predetermined speed NE(0), and the throttle opening TH is equal to or larger than the predetermined opening TH(0) If all are satisfied (YES in step S502), the air pump 200 is operated (S504). the

If the air pump 200 is operated when the AI is not implemented (i.e., the solenoid ASV 212, vacuum pressure ASV(1) 222, and vacuum pressure ASV(2) 232 are off), the air delivered from the air pump 200 under pressure is Confined in the first air passage 210 . Therefore, the operating noise of the air pump 200 becomes louder. Therefore, the vehicle owner may feel uncomfortable due to the noise of the air pump 200 . the

However, when the vehicle speed V is equal to or higher than the predetermined vehicle speed V(0), the engine speed NE is equal to or higher than the predetermined speed NE(0), and the throttle opening TH is equal to or greater than the predetermined opening TH(0), the road noise Also, the running noise and exhaust noise of the engine 100 are large. When operating the air pump 200 under such conditions, it is difficult for the owner to hear the operating noise of the air pump 200 due to road noise, operating noise and exhaust noise of the engine 100 . Therefore, it is possible to reduce the possibility that the vehicle owner feels uncomfortable due to the operating noise of the air pump 200 . the

When the air pump 200 is operated (S504), the pressure in the first air passage 210 is detected (S506). Since air is delivered under pressure when the air pump 200 is operated, the pressure inside the first air passage 210 increases. Therefore, if the pressure sensor 306 is normal, the pressure detected by the pressure sensor 306 increases. the

Therefore, if the pressure has increased (YES in step S508), it is determined that the pressure sensor 306 is normal (S510). Meanwhile, if the pressure has not increased ("No" in step S508), it is determined that a failure has occurred in the pressure sensor 306. the

As described above, in this embodiment, when the vehicle speed V is equal to or higher than the predetermined vehicle speed V(0), the engine rotational speed NE is equal to or higher than the predetermined rotational speed NE(0), and the throttle opening TH is equal to or greater than the predetermined opening. At TH(0), run the air pump and determine if a failure has occurred in the pressure sensor. Then, the running noise of the air pump can be masked by the road noise as well as the running noise and exhaust noise of the engine. As a result, it is possible to reduce the likelihood that the vehicle owner will feel uncomfortable due to the operating noise of the air pump. the

Therefore, the embodiments of the present invention disclosed in the specification should be considered in every respect as illustrative rather than restrictive. The technical scope of the present invention is defined by the claims, and thus, all modifications falling within the meaning and range of equivalents of the claims are included in the scope of the present invention. the

Claims (9)

1. A secondary air supply apparatus for an internal combustion engine provided with a plurality of cylinders, the secondary air supply apparatus supplies secondary air to a portion upstream of an exhaust gas control device, characterized by comprising: an air pump supplying air under pressure; a first air passage through which said air delivered under pressure from said air pump can flow; opening/closing a first opening/closing valve of the first air passage; a second air passage whose one end is connected to the first air passage at a portion downstream of the first opening/closing valve and whose other end is connected to an exhaust gas leading to a predetermined cylinder among the plurality of cylinders aisle; opening/closing a second opening/closing valve of the second air passage; A third air passage, one end of which is connected to the first air passage at a portion downstream of the first opening/closing valve, and the other end of which is connected to the cylinder to which the exhaust passage leads and connected to the The predetermined cylinders to which the exhaust passages of the second air passage lead are different; a third opening/closing valve that opens/closes the third air passage; a pressure detector for detecting pressure in the first air passage, the pressure detector being disposed between the air pump and the first opening/closing valve; a failure determination device, wherein the failure determination device is controlled to open the first opening/closing valve, the second opening/closing valve and the third opening/closing valve are controlled to close, and the air pump is controlled When stopping, it is determined whether a failure has occurred in the secondary air supply device based on the result of detection performed by the pressure detector. 2. The secondary air supply device according to claim 1, wherein said failure determining means determines whether a malfunction has occurred in said secondary air supply device when the amount of air introduced into said internal combustion engine is larger than a predetermined amount. Fault. 3. The secondary air supply device according to claim 1 or 2, wherein the failure determination means determines that a failure has occurred in the secondary air supply device when a change in pressure is detected by the pressure detector . 4. The secondary air supply apparatus according to claim 1 or 2, wherein said failure determining means determines whether at least one of said second opening/closing valve and said third opening/closing valve has malfunction. 5. A secondary air supply apparatus for an internal combustion engine installed in a vehicle, which supplies secondary air to a portion upstream of an exhaust control device, characterized by comprising: a pressure detector detecting the pressure of the secondary air delivered under pressure from the air pump to the channel connected to the exhaust channel; a pump operating device, which is greater than predetermined in magnitude representing at least one of a vehicle speed, a rotational speed of the internal combustion engine, and an opening degree of a throttle valve provided in the internal combustion engine, in relation to noise heard by the owner of the vehicle When the value is set, the air pump is operated; A failure determination means determines whether a failure has occurred in the secondary air supply device based on a result of detection performed by the pressure detector while the air pump is operated under control. 6. The secondary air supply apparatus according to claim 5, wherein the internal combustion engine is provided with a plurality of cylinders, wherein, The secondary air supply device includes: i) a first air passage through which the air delivered under pressure from the air pump can flow; ii) opening/closing the first air passage the first open/close valve; iii) a second air passage connected to the first air passage at a portion downstream of the first open/close valve, and connected to the air passage leading to the plurality of cylinders iv) a second opening/closing valve that opens/closes the second air passage; v) a third air passage that is at a portion downstream of the first opening/closing valve connected to said first air passage and connected to an exhaust passage leading to a cylinder different from said intended cylinder to which said exhaust passage connected to said second air passage leads; vi) open /closing a third opening/closing valve of said third air passage; The failure determining means determines based on a result of detection performed by the pressure detector when the first opening/closing valve, the second opening/closing valve, and the third opening/closing valve are controlled closed. It is determined whether a malfunction has occurred in the secondary air supply device. 7. The secondary air detection device according to claim 6, wherein said failure determination means determines that a failure has occurred in said secondary air supply device when said pressure detector does not detect a pressure increase. 8. The secondary air supply apparatus according to claim 5, wherein said failure determining means determines whether at least one of said pressure detector and said air pump has failed. 9. A secondary air supply method for controlling secondary air supplied to a portion upstream of an exhaust control device, comprising the steps of: The following means are provided: an air pump supplying air under pressure; a first opening/closing valve opening/closing a first air passage through which said air delivered from said air pump under pressure can flow passage; a second open/close valve that opens/closes the second air passage connected to the first air passage at a portion downstream of the first open/close valve, and the The second air passage is connected to an exhaust passage leading to a predetermined cylinder among the plurality of cylinders; a third opening/closing valve that opens/closes the third air passage in the first air passage A downstream portion of an open/close valve is connected to the first air passage, and the third air passage is connected to the cylinder to which the exhaust passage leads and to the exhaust passage connected to the second air passage. The predetermined cylinders to which the air passages lead are different; detecting a pressure in the first air passage between the air pump and the first open/close valve; When the first open/close valve is opened under control, the second open/close valve and the third open/close valve are closed under control, and the air pump is stopped under control, based on the pressure detection It is determined whether a failure has occurred in the second air supply device based on the result of the detection performed by the device.

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